The overall goal of this research is to contribute to the understanding of the biochemical mechanisms of the induction of periodontal disease in man. The biosynthesis of cell surface carbohydrate antigens will be studied in Actinomyces viscosus T14, a human oral bacterium that forms plaque and evokes periodontal disease in experimental animals. The major neutral sugars of the cell wall are rhamnose and 6-deoxytalose (DOT). The linkage between carbohydrate and peptidoglycan will be probed by hydrolytic procedures that are selective for phosphodiesters, and by overall chemical analysis. These studies will indicate the nature of nucleotide sugar substrates that are required for cell wall biosynthesis. The assembly of cell wall subunits will be studied in chemiclly treated whole cells. If the DOT-containing antigen is essential in the pathogenicity of A. viscosus T14, the absence of DOT is mammalian tissues offers hope that agents, which could block either its synthesis or its incorporation into polymers by Actinomyces, would be innocuous to man and might be useful in suppressing the pathogenicity of Actinomyces in dental plaque. Accordingly, an understanding of the biosynthesis of the DOT-containing polymers should expedite the dicovery of such useful agents. Success in the endeavor might set a pattern of investigation which, through application to other oral pathogens, might contribute in a major way to the control of periodontal disease and caries.